Even the earliest computer system included a rudimentary mechanism that allowed it to receive input from its users. These mechanisms are often called user interfaces. The user interfaces of early computers often employed lights and switches that allowed the computer system user to communicate with the computer system in the system's native language. While this form of communication was effective, its use was essentially limited to scientists and engineers who were trained to understand the particulars of the computer system. For this reason, computer system providers moved to user interfaces that provided for entry of textual commands. While these command-based user interfaces were easier to use than their predecessors, they still typically involved a large number of commands that were often difficult for non-technical individuals to understand and remember. The shortcomings of command-based user interfaces led to the introduction of graphical user interfaces, which are often referred to as GUIs. Instead of requiring the user to have in-depth knowledge of the computer system, graphical user interfaces allow the every day user to communicate with the computer system via a pointing device such as a mouse. To use the computer system to perform various tasks, the user simply "points and clicks" on various GUI items such as icons and taskbars. These icons and taskbars are user friendly ways of activating different programs on the computer.
After a program has been activated, it will often portray itself to the user in the form of another GUI item called a window. The term window is chosen because, like regular windows in a house or office building, what can be seen through the window represents only a portion of the object that is being viewed. For this reason, windows often include what is referred to as a scroll bar. Scroll bars typically include long rectangular shafts that house a scroll box (sometimes called a puck, slider, or thumb). The user is allowed to move the scroll box up and down the scroll bar shaft to bring different portions of the object into view. Scroll bars also typically include "up arrows" and "down arrows," which also allow the user to see different portions of the object being viewed.
Scroll boxes are typically used within windows to provide what we will call coarse access to the underlying object. Up arrows and down arrows, on the other hand, are typically used to provide the user with what we will call fine access. To make this point more clear, consider an object that is made up of several pages of text (e.g., a large document). When a user is looking at this type of object through a GUI window, he or she is able to see only a portion of the object (i.e., perhaps only a page or slightly more). The user then moves the scroll box or the up or down arrows to view the other pages of the object. If the user wants to move several pages forward or backward, the scroll box will be used, but if the user wants to move only a short distance, perhaps only a line or two, the up or down arrows are used.
One problem with today's scroll bars involves the access or viewing of large objects. Simply stated, the coarse access provided by scroll boxes to large objects is too coarse and the fine access provided to large objects by the up and down arrows is too fine. This problem can often frustrate a user because when he or she wants to move to a particular place (e.g., a page), use of the scroll box causes the user to "fly by" their location of interest, while use of the up or down arrows seemingly takes an eternity. Another problem with today's scroll box/arrow design is that the user must move off of the scroll box after coarse access to the arrows to gain fine access and move off of the arrows after fine access to the scroll box to gain coarse access. This design is inefficient and time consuming because it causes the user to waste time moving back and forth.
Given that a program's "usability" or friendliness is a large factor in a user's value assessment, these access problems can have a negative impact on program provider sales. It is clear, then, that a scroll bar with improved access capabilities represents a valuable addition to the art.